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James Hansen's articles

If It's That Warm, How Come It's So Darned Cold?

Explaining Regional Cold Spells in the Context of High Global Temperatures 

By James Hansen

Jan 29, 2010

(The following is an excerpt of the overview section of a paper by James Hansen, Reto Ruedy, Makiko Sato, and Ken Lo. )

Public skepticism about global warming was reinforced by the extreme cold of December 2009 in the contiguous 48 United States and in much of Eurasia. The summer of 2009 was also unusually cool in the United States. But when a cold spell hits, we need to ask:

  • Cold compared to what. Our memory of the past few winters? Winters of our childhood? Winters earlier in the 20th century?
  • Cold where and for how long? Regional cold snaps are expected even with large global warming. Weather fluctuations can be 10, 20 or 30 degrees, much larger than average global warming.
  • The reality of seasons. As the plot of Earth we live on turns away from the sun, in
    winter or at night, it cools off. That’s true even with global warming, albeit not quite so much.

Before addressing these matters, we note that scientists reporting global warming have come under attack for a supposed conspiracy to manufacture evidence of global warming. Perhaps because some members of the public accept these charges as reality, vicious personal messages are sent to the principal scientists almost daily.

The spiral into an almost surrealistic situation with ad hominem attacks on scientists may have originated in part with vested interests who do not want society to address climate change. But there is more than that – including honest, wishful thinking that climate change is not really happening. But wishing does not alter facts.

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The People vs. Cap‐and‐Tax

By James Hansen

Jan 13, 2010

The public is largely unaware of a momentous battle about to be fought in Washington. The stakes are enormous. Yet the public has not been well informed.

Ignorance of the matter derives in part from the fact that the conflict was initiated via the highly charged issue of climate change. Climate is complex. People have different opinions about the extent to which humans are causing climate change. Fundamental belief systems are involved and discussion can be emotional.

Yet the core issue can be defined independent of climate. It concerns how society can phase out its addictive use of fossil fuels and move on, in the most economically efficient and equitable way, to a clean energy future.

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Ice Core Samples Reveal Black Soot Threatening Tibetan Glaciers

Earth's 'Third Pole' Melting at Alarming Pace

By James Hansen

Dec 17, 2009

Glaciers on the Tibetan Plateau, sometimes called Earth's "third pole," hold the largest ice mass outside the polar regions.

These glaciers act as water storage towers for South and East Asia, releasing melt water in warm months to the Indus, Ganges, Brahmaputra and other river systems that provide fresh water to more than a billion people. In the dry season, glacial melt provides half or more of the water in many rivers.

Glacier changes depend on local weather, especially snowfall, so glacier retreat or advance fluctuates with time and place. Thus, it is inevitable that some Tibetan glaciers advance over short periods, as has been reported. But overall, Tibetan glaciers are retreating at an alarming rate.

Global warming must be the primary cause of glacier retreat, which is occurring on a global scale, but observed rapid melt rates suggest that other factors may be involved. To investigate, a team of scientists from Chinese research institutes extracted ice cores from five locations on the Tibetan Plateau.

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Why We Must Phase out Coal Emissions

By James Hansen

Nov 24, 2009

My grandchildren began to influence me when I realized that policy makers were ignoring the message from the climate science, or rather that politicians were developing the fine art of greenwash — they would say favorable words about the environment and stabilizing climate, but their actions were inconsistent with that goal.

Politicians would be happy if scientists just tell them there is a climate problem and then go away and shut up. Let them decide what they want to do.

But I decided that I did not want my grandchildren, some day in the future, to look back and say, “Opa understood what was happening, but he did not make it clear.”

What is clear is that we cannot burn all the fossil fuels. There is a limit on how much carbon we can put into the atmosphere.

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Tipping Points: Melting Ice, Rising Oceans

By James Hansen

Nov 23, 2009

Global warming IS a time bomb.

There may still be time to defuse it, but that requires policy-makers to take the actions that are needed, not the ineffectual actions they are discussing.

Despite the publicity that global warming has received, there is a large gap between what is understood by the relevant scientific community, and what is known by the people who need to know, the public and policymakers. Global warming is small compared to day-to-day weather fluctuations, so it is hard for people to recognize that we have a crisis – but we do.

The climate system has great inertia, caused, e.g., by the 4-kilometer-deep ocean and the thick ice sheets on Antarctica and Greenland, which have only partly responded to the human-made changes of atmospheric composition. That inertia is not our friend. It is a Trojan horse. By the time the public notices that change is underway the momentum of the climate system may be sufficient to guarantee much larger changes. The climate system can pass tipping points, such that large change continues out of our control.

The bad news is that we have already passed into a dangerous range of atmospheric carbon dioxide.

The good news is that if we act smart and promptly it is still feasible to achieve a safe level of atmospheric gases, and the actions needed to achieve that would have multiple benefits in addition to climate stability.

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James Hansen on Climate Tipping Points and Political Leadership

By James Hansen

Jul 15, 2009

In my opinion, it is still feasible to solve the global warming problem before we pass tipping points that would guarantee disastrous irreversible climate change. But urgent strong actions are needed.

It is clear that the required course is technically feasible, and it would have great benefits to the public in developing and developed countries. The geophysical facts practically dictate the way.

Unfortunately, knowledge and understanding of the situation are not widespread. In addition, there is a minority of people, termed “fossil interests,” who benefit from business-as-usual. These fossil interests have enormous influence on governments worldwide, far outside their fair role in democracies.

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G8 Failure Reflects Congress' Failure to Write Effective Climate Policy

By James Hansen

Jul 10, 2009

It didn't take long for the counterfeit climate bill known as Waxman-Markey to push back against President Obama's agenda.

As the president was arriving in Italy for his first Group of Eight summit, The New York Times was that efforts to close ranks on global warming between the G-8 and the emerging economies had already tanked:

The world's major industrial nations and emerging powers failed to agree Wednesday on significant cuts in heat-trapping gases by 2050, unraveling an effort to build a global consensus to fight climate change, according to people following the talks.

Of course, emission targets in 2050 have limited practical meaning — present leaders will be dead or doddering by then — so these differences may be patched up. The important point is that other nations are unlikely to make real concessions on emissions if the United States is not addressing the climate matter seriously.

With a workable climate bill in his pocket, President Obama might have been able to begin building that global consensus in Italy.

Instead, it looks as if the delegates from other nations may have done what 219 U.S. House members who voted up Waxman-Markey last month did not: critically read the 1,400-page and deduce that it's no more fit to rescue our climate than a V-2 rocket was to land a man on the moon.

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Cap-and-Trade is the Temple of Doom

By James Hansen

May 6, 2009

It is easy to speak of a planet in peril. It is quite another to level with the public about what is needed, even if the actions are in everybody’s long-term interest.

Instead, governments are retreating to feckless “cap-and-trade”, a minor tweak to business-as-usual.

Oil companies are so relieved to realize that they do not need to learn to be energy companies that they are decreasing their already trivial investments in renewable energy.

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